PHP Traversable type hint

Question

I have a relatively simple function which uses a foreach

function foo($t) {
     $result;
     foreach($t as $val) {
         $result = dosometh         


        

Answer 1

There is a bug about this: #41942. Closed as 'not a bug'. As PHP arrays are not objects they cannot implement an interface and a such there is no way to type hint both array and Traversable.

You can use iterator_to_array, ArrayIterator or omit the type hint. Note that iterator_to_array will copy the whole iterator into an array an might thus be inefficient.

// These functions are functionally equivalent but do not all accept the same arguments
function foo(array $a) { foobar($a); }
function bar(Traversable $a) { foobar($a); }
function foobar($a) {
    foreach($a as $key => $value) {
    }
}

$array = array(1,2,3)
$traversable = new MyTraversableObject();

foo($array);
foo(iterator_to_array($traversable));

bar(new ArrayIterator($array));
bar($traversable);

foobar($array);
foobar($traversable);